Im quite new to ODOO, and
currently experiencing issue below on our deployed ODOO version 7.

Thus, A message is sent to all
staff ,any member of staff replies to the message and it gets received by all
staff(as long as the staff is a member of the group "whole company").
Also, any staff can deceide to send message to all satff.

The question is how to restrict
staff from sending message to entire company.